Source/JavaScriptCore/runtime/JSBoundFunction.cpp - WebKit - Git at Google

 /*
  * Copyright (C) 2011, 2016-2017 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include "config.h"
 #include "JSBoundFunction.h"

 #include "ExecutableBaseInlines.h"
 #include "GetterSetter.h"
 #include "JSGlobalObject.h"
 #include "JSCInlines.h"

 namespace JSC {

 const ClassInfo JSBoundFunction::s_info = { "Function", &Base::s_info, nullptr, nullptr, CREATE_METHOD_TABLE(JSBoundFunction) };

 EncodedJSValue JSC_HOST_CALL boundThisNoArgsFunctionCall(JSGlobalObject* globalObject, CallFrame* callFrame)
 {
     JSBoundFunction* boundFunction = jsCast<JSBoundFunction*>(callFrame->jsCallee());

     JSImmutableButterfly* boundArgs = boundFunction->boundArgs();

     MarkedArgumentBuffer args;
     if (boundArgs) {
         // Starts with 1 since the first one is |this|.
         for (unsigned i = 1; i < boundArgs->length(); ++i)
             args.append(boundArgs->get(i));
     }
     for (unsigned i = 0; i < callFrame->argumentCount(); ++i)
         args.append(callFrame->uncheckedArgument(i));
     RELEASE_ASSERT(!args.hasOverflowed());

     JSFunction* targetFunction = jsCast<JSFunction*>(boundFunction->targetFunction());
     ExecutableBase* executable = targetFunction->executable();
     if (executable->hasJITCodeForCall()) {
         // Force the executable to cache its arity entrypoint.
         executable->entrypointFor(CodeForCall, MustCheckArity);
     }
     CallData callData;
     CallType callType = getCallData(globalObject->vm(), targetFunction, callData);
     ASSERT(callType != CallType::None);
     return JSValue::encode(call(globalObject, targetFunction, callType, callData, boundFunction->boundThis(), args));
 }

 EncodedJSValue JSC_HOST_CALL boundFunctionCall(JSGlobalObject* globalObject, CallFrame* callFrame)
 {
     VM& vm = globalObject->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);
     JSBoundFunction* boundFunction = jsCast<JSBoundFunction*>(callFrame->jsCallee());

     JSImmutableButterfly* boundArgs = boundFunction->boundArgs();

     MarkedArgumentBuffer args;
     if (boundArgs) {
         // Starts with 1 since the first one is |this|.
         for (unsigned i = 1; i < boundArgs->length(); ++i)
             args.append(boundArgs->get(i));
     }
     for (unsigned i = 0; i < callFrame->argumentCount(); ++i)
         args.append(callFrame->uncheckedArgument(i));
     if (UNLIKELY(args.hasOverflowed())) {
         throwOutOfMemoryError(globalObject, scope);
         return encodedJSValue();
     }

     JSObject* targetFunction = boundFunction->targetFunction();
     CallData callData;
     CallType callType = getCallData(vm, targetFunction, callData);
     ASSERT(callType != CallType::None);
     RELEASE_AND_RETURN(scope, JSValue::encode(call(globalObject, targetFunction, callType, callData, boundFunction->boundThis(), args)));
 }

 EncodedJSValue JSC_HOST_CALL boundThisNoArgsFunctionConstruct(JSGlobalObject* globalObject, CallFrame* callFrame)
 {
     JSBoundFunction* boundFunction = jsCast<JSBoundFunction*>(callFrame->jsCallee());

     JSImmutableButterfly* boundArgs = boundFunction->boundArgs();

     MarkedArgumentBuffer args;
     if (boundArgs) {
         // Starts with 1 since the first one is |this|.
         for (unsigned i = 1; i < boundArgs->length(); ++i)
             args.append(boundArgs->get(i));
     }
     for (unsigned i = 0; i < callFrame->argumentCount(); ++i)
         args.append(callFrame->uncheckedArgument(i));
     RELEASE_ASSERT(!args.hasOverflowed());

     JSFunction* targetFunction = jsCast<JSFunction*>(boundFunction->targetFunction());
     ConstructData constructData;
     ConstructType constructType = getConstructData(globalObject->vm(), targetFunction, constructData);
     ASSERT(constructType != ConstructType::None);
     return JSValue::encode(construct(globalObject, targetFunction, constructType, constructData, args));
 }

 EncodedJSValue JSC_HOST_CALL boundFunctionConstruct(JSGlobalObject* globalObject, CallFrame* callFrame)
 {
     VM& vm = globalObject->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);
     JSBoundFunction* boundFunction = jsCast<JSBoundFunction*>(callFrame->jsCallee());

     JSImmutableButterfly* boundArgs = boundFunction->boundArgs();

     MarkedArgumentBuffer args;
     if (boundArgs) {
         // Starts with 1 since the first one is |this|.
         for (unsigned i = 1; i < boundArgs->length(); ++i)
             args.append(boundArgs->get(i));
     }
     for (unsigned i = 0; i < callFrame->argumentCount(); ++i)
         args.append(callFrame->uncheckedArgument(i));
     if (UNLIKELY(args.hasOverflowed())) {
         throwOutOfMemoryError(globalObject, scope);
         return encodedJSValue();
     }

     JSObject* targetFunction = boundFunction->targetFunction();
     ConstructData constructData;
     ConstructType constructType = getConstructData(vm, targetFunction, constructData);
     ASSERT(constructType != ConstructType::None);
     RELEASE_AND_RETURN(scope, JSValue::encode(construct(globalObject, targetFunction, constructType, constructData, args)));
 }

 EncodedJSValue JSC_HOST_CALL isBoundFunction(JSGlobalObject* globalObject, CallFrame* callFrame)
 {
     return JSValue::encode(JSValue(static_cast<bool>(jsDynamicCast<JSBoundFunction*>(globalObject->vm(), callFrame->uncheckedArgument(0)))));
 }

 EncodedJSValue JSC_HOST_CALL hasInstanceBoundFunction(JSGlobalObject* globalObject, CallFrame* callFrame)
 {
     JSBoundFunction* boundObject = jsCast<JSBoundFunction*>(callFrame->uncheckedArgument(0));
     JSValue value = callFrame->uncheckedArgument(1);

     return JSValue::encode(jsBoolean(boundObject->targetFunction()->hasInstance(globalObject, value)));
 }

 inline Structure* getBoundFunctionStructure(VM& vm, JSGlobalObject* globalObject, JSObject* targetFunction)
 {
     auto scope = DECLARE_THROW_SCOPE(vm);
     JSValue prototype = targetFunction->getPrototype(vm, globalObject);
     RETURN_IF_EXCEPTION(scope, nullptr);
     JSFunction* targetJSFunction = jsDynamicCast<JSFunction*>(vm, targetFunction);

     // We only cache the structure of the bound function if the bindee is a JSFunction since there
     // isn't any good place to put the structure on Internal Functions.
     if (targetJSFunction) {
         Structure* structure = targetJSFunction->ensureRareData(vm)->getBoundFunctionStructure();
         if (structure && structure->storedPrototype() == prototype && structure->globalObject() == globalObject)
             return structure;
     }

     Structure* result = globalObject->boundFunctionStructure();

     // It would be nice if the structure map was keyed global objects in addition to the other things. Unfortunately, it is not
     // currently. Whoever works on caching structure changes for prototype transitions should consider this problem as well.
     // See: https://bugs.webkit.org/show_bug.cgi?id=152738
     if (prototype.isObject() && prototype.getObject()->globalObject(vm) == globalObject) {
         result = vm.structureCache.emptyStructureForPrototypeFromBaseStructure(globalObject, prototype.getObject(), result);
         ASSERT_WITH_SECURITY_IMPLICATION(result->globalObject() == globalObject);
     } else
         result = Structure::create(vm, globalObject, prototype, result->typeInfo(), result->classInfo());

     if (targetJSFunction)
         targetJSFunction->ensureRareData(vm)->setBoundFunctionStructure(vm, result);

     return result;
 }

 JSBoundFunction* JSBoundFunction::create(VM& vm, JSGlobalObject* globalObject, JSObject* targetFunction, JSValue boundThis, JSImmutableButterfly* boundArgs, int length, JSString* nameMayBeNull)
 {
     auto scope = DECLARE_THROW_SCOPE(vm);

     if (nameMayBeNull) {
         nameMayBeNull->value(globalObject); // Resolving rope.
         RETURN_IF_EXCEPTION(scope, nullptr);
     }

     bool isJSFunction = getJSFunction(targetFunction);
     ConstructData constructData;
     ConstructType constructType = JSC::getConstructData(vm, targetFunction, constructData);
     bool canConstruct = constructType != ConstructType::None;

     NativeExecutable* executable = vm.getBoundFunction(isJSFunction, canConstruct);
     Structure* structure = getBoundFunctionStructure(vm, globalObject, targetFunction);
     RETURN_IF_EXCEPTION(scope, nullptr);
     JSBoundFunction* function = new (NotNull, allocateCell<JSBoundFunction>(vm.heap)) JSBoundFunction(vm, executable, globalObject, structure, targetFunction, boundThis, boundArgs, nameMayBeNull, length);

     function->finishCreation(vm, executable, length);
     return function;
 }

 bool JSBoundFunction::customHasInstance(JSObject* object, JSGlobalObject* globalObject, JSValue value)
 {
     return jsCast<JSBoundFunction*>(object)->m_targetFunction->hasInstance(globalObject, value);
 }

 JSBoundFunction::JSBoundFunction(VM& vm, NativeExecutable* executable, JSGlobalObject* globalObject, Structure* structure, JSObject* targetFunction, JSValue boundThis, JSImmutableButterfly* boundArgs, JSString* nameMayBeNull, int length)
     : Base(vm, executable, globalObject, structure)
     , m_targetFunction(vm, this, targetFunction)
     , m_boundThis(vm, this, boundThis)
     , m_boundArgs(vm, this, boundArgs, WriteBarrier<JSImmutableButterfly>::MayBeNull)
     , m_nameMayBeNull(vm, this, nameMayBeNull, WriteBarrier<JSString>::MayBeNull)
     , m_length(length)
 {
     ASSERT(!m_nameMayBeNull || !m_nameMayBeNull->isRope());
 }

 JSArray* JSBoundFunction::boundArgsCopy(JSGlobalObject* globalObject)
 {
     VM& vm = globalObject->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);
     JSArray* result = constructEmptyArray(this->globalObject(), nullptr);
     RETURN_IF_EXCEPTION(scope, nullptr);
     if (m_boundArgs) {
         // Starts with 1 since the first one is bound |this|.
         for (unsigned i = 1; i < m_boundArgs->length(); ++i) {
             result->push(globalObject, m_boundArgs->get(i));
             RETURN_IF_EXCEPTION(scope, nullptr);
         }
     }
     return result;
 }

 void JSBoundFunction::finishCreation(VM& vm, NativeExecutable* executable, int length)
 {
     String name; // We lazily create our 'name' string property.
     Base::finishCreation(vm, executable, length, name);
     ASSERT(inherits(vm, info()));
 }

 void JSBoundFunction::visitChildren(JSCell* cell, SlotVisitor& visitor)
 {
     JSBoundFunction* thisObject = jsCast<JSBoundFunction*>(cell);
     ASSERT_GC_OBJECT_INHERITS(thisObject, info());
     Base::visitChildren(thisObject, visitor);

     visitor.append(thisObject->m_targetFunction);
     visitor.append(thisObject->m_boundThis);
     visitor.append(thisObject->m_boundArgs);
     visitor.append(thisObject->m_nameMayBeNull);
 }

 } // namespace JSC
	/*
	* Copyright (C) 2011, 2016-2017 Apple Inc. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
	* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
	* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
	* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
	* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
	* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
	* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include "config.h"
	#include "JSBoundFunction.h"

	#include "ExecutableBaseInlines.h"
	#include "GetterSetter.h"
	#include "JSGlobalObject.h"
	#include "JSCInlines.h"

	namespace JSC {

	const ClassInfo JSBoundFunction::s_info = { "Function", &Base::s_info, nullptr, nullptr, CREATE_METHOD_TABLE(JSBoundFunction) };

	EncodedJSValue JSC_HOST_CALL boundThisNoArgsFunctionCall(JSGlobalObject* globalObject, CallFrame* callFrame)
	{
	JSBoundFunction* boundFunction = jsCast<JSBoundFunction*>(callFrame->jsCallee());

	JSImmutableButterfly* boundArgs = boundFunction->boundArgs();

	MarkedArgumentBuffer args;
	if (boundArgs) {
	// Starts with 1 since the first one is \|this\|.
	for (unsigned i = 1; i < boundArgs->length(); ++i)
	args.append(boundArgs->get(i));
	}
	for (unsigned i = 0; i < callFrame->argumentCount(); ++i)
	args.append(callFrame->uncheckedArgument(i));
	RELEASE_ASSERT(!args.hasOverflowed());

	JSFunction* targetFunction = jsCast<JSFunction*>(boundFunction->targetFunction());
	ExecutableBase* executable = targetFunction->executable();
	if (executable->hasJITCodeForCall()) {
	// Force the executable to cache its arity entrypoint.
	executable->entrypointFor(CodeForCall, MustCheckArity);
	}
	CallData callData;
	CallType callType = getCallData(globalObject->vm(), targetFunction, callData);
	ASSERT(callType != CallType::None);
	return JSValue::encode(call(globalObject, targetFunction, callType, callData, boundFunction->boundThis(), args));
	}

	EncodedJSValue JSC_HOST_CALL boundFunctionCall(JSGlobalObject* globalObject, CallFrame* callFrame)
	{
	VM& vm = globalObject->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);
	JSBoundFunction* boundFunction = jsCast<JSBoundFunction*>(callFrame->jsCallee());

	JSImmutableButterfly* boundArgs = boundFunction->boundArgs();

	MarkedArgumentBuffer args;
	if (boundArgs) {
	// Starts with 1 since the first one is \|this\|.
	for (unsigned i = 1; i < boundArgs->length(); ++i)
	args.append(boundArgs->get(i));
	}
	for (unsigned i = 0; i < callFrame->argumentCount(); ++i)
	args.append(callFrame->uncheckedArgument(i));
	if (UNLIKELY(args.hasOverflowed())) {
	throwOutOfMemoryError(globalObject, scope);
	return encodedJSValue();
	}

	JSObject* targetFunction = boundFunction->targetFunction();
	CallData callData;
	CallType callType = getCallData(vm, targetFunction, callData);
	ASSERT(callType != CallType::None);
	RELEASE_AND_RETURN(scope, JSValue::encode(call(globalObject, targetFunction, callType, callData, boundFunction->boundThis(), args)));
	}

	EncodedJSValue JSC_HOST_CALL boundThisNoArgsFunctionConstruct(JSGlobalObject* globalObject, CallFrame* callFrame)
	{
	JSBoundFunction* boundFunction = jsCast<JSBoundFunction*>(callFrame->jsCallee());

	JSImmutableButterfly* boundArgs = boundFunction->boundArgs();

	MarkedArgumentBuffer args;
	if (boundArgs) {
	// Starts with 1 since the first one is \|this\|.
	for (unsigned i = 1; i < boundArgs->length(); ++i)
	args.append(boundArgs->get(i));
	}
	for (unsigned i = 0; i < callFrame->argumentCount(); ++i)
	args.append(callFrame->uncheckedArgument(i));
	RELEASE_ASSERT(!args.hasOverflowed());

	JSFunction* targetFunction = jsCast<JSFunction*>(boundFunction->targetFunction());
	ConstructData constructData;
	ConstructType constructType = getConstructData(globalObject->vm(), targetFunction, constructData);
	ASSERT(constructType != ConstructType::None);
	return JSValue::encode(construct(globalObject, targetFunction, constructType, constructData, args));
	}

	EncodedJSValue JSC_HOST_CALL boundFunctionConstruct(JSGlobalObject* globalObject, CallFrame* callFrame)
	{
	VM& vm = globalObject->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);
	JSBoundFunction* boundFunction = jsCast<JSBoundFunction*>(callFrame->jsCallee());

	JSImmutableButterfly* boundArgs = boundFunction->boundArgs();

	MarkedArgumentBuffer args;
	if (boundArgs) {
	// Starts with 1 since the first one is \|this\|.
	for (unsigned i = 1; i < boundArgs->length(); ++i)
	args.append(boundArgs->get(i));
	}
	for (unsigned i = 0; i < callFrame->argumentCount(); ++i)
	args.append(callFrame->uncheckedArgument(i));
	if (UNLIKELY(args.hasOverflowed())) {
	throwOutOfMemoryError(globalObject, scope);
	return encodedJSValue();
	}

	JSObject* targetFunction = boundFunction->targetFunction();
	ConstructData constructData;
	ConstructType constructType = getConstructData(vm, targetFunction, constructData);
	ASSERT(constructType != ConstructType::None);
	RELEASE_AND_RETURN(scope, JSValue::encode(construct(globalObject, targetFunction, constructType, constructData, args)));
	}

	EncodedJSValue JSC_HOST_CALL isBoundFunction(JSGlobalObject* globalObject, CallFrame* callFrame)
	{
	return JSValue::encode(JSValue(static_cast<bool>(jsDynamicCast<JSBoundFunction*>(globalObject->vm(), callFrame->uncheckedArgument(0)))));
	}

	EncodedJSValue JSC_HOST_CALL hasInstanceBoundFunction(JSGlobalObject* globalObject, CallFrame* callFrame)
	{
	JSBoundFunction* boundObject = jsCast<JSBoundFunction*>(callFrame->uncheckedArgument(0));
	JSValue value = callFrame->uncheckedArgument(1);

	return JSValue::encode(jsBoolean(boundObject->targetFunction()->hasInstance(globalObject, value)));
	}

	inline Structure* getBoundFunctionStructure(VM& vm, JSGlobalObject* globalObject, JSObject* targetFunction)
	{
	auto scope = DECLARE_THROW_SCOPE(vm);
	JSValue prototype = targetFunction->getPrototype(vm, globalObject);
	RETURN_IF_EXCEPTION(scope, nullptr);
	JSFunction* targetJSFunction = jsDynamicCast<JSFunction*>(vm, targetFunction);

	// We only cache the structure of the bound function if the bindee is a JSFunction since there
	// isn't any good place to put the structure on Internal Functions.
	if (targetJSFunction) {
	Structure* structure = targetJSFunction->ensureRareData(vm)->getBoundFunctionStructure();
	if (structure && structure->storedPrototype() == prototype && structure->globalObject() == globalObject)
	return structure;
	}

	Structure* result = globalObject->boundFunctionStructure();

	// It would be nice if the structure map was keyed global objects in addition to the other things. Unfortunately, it is not
	// currently. Whoever works on caching structure changes for prototype transitions should consider this problem as well.
	// See: https://bugs.webkit.org/show_bug.cgi?id=152738
	if (prototype.isObject() && prototype.getObject()->globalObject(vm) == globalObject) {
	result = vm.structureCache.emptyStructureForPrototypeFromBaseStructure(globalObject, prototype.getObject(), result);
	ASSERT_WITH_SECURITY_IMPLICATION(result->globalObject() == globalObject);
	} else
	result = Structure::create(vm, globalObject, prototype, result->typeInfo(), result->classInfo());

	if (targetJSFunction)
	targetJSFunction->ensureRareData(vm)->setBoundFunctionStructure(vm, result);

	return result;
	}

	JSBoundFunction* JSBoundFunction::create(VM& vm, JSGlobalObject* globalObject, JSObject* targetFunction, JSValue boundThis, JSImmutableButterfly* boundArgs, int length, JSString* nameMayBeNull)
	{
	auto scope = DECLARE_THROW_SCOPE(vm);

	if (nameMayBeNull) {
	nameMayBeNull->value(globalObject); // Resolving rope.
	RETURN_IF_EXCEPTION(scope, nullptr);
	}

	bool isJSFunction = getJSFunction(targetFunction);
	ConstructData constructData;
	ConstructType constructType = JSC::getConstructData(vm, targetFunction, constructData);
	bool canConstruct = constructType != ConstructType::None;

	NativeExecutable* executable = vm.getBoundFunction(isJSFunction, canConstruct);
	Structure* structure = getBoundFunctionStructure(vm, globalObject, targetFunction);
	RETURN_IF_EXCEPTION(scope, nullptr);
	JSBoundFunction* function = new (NotNull, allocateCell<JSBoundFunction>(vm.heap)) JSBoundFunction(vm, executable, globalObject, structure, targetFunction, boundThis, boundArgs, nameMayBeNull, length);

	function->finishCreation(vm, executable, length);
	return function;
	}

	bool JSBoundFunction::customHasInstance(JSObject* object, JSGlobalObject* globalObject, JSValue value)
	{
	return jsCast<JSBoundFunction*>(object)->m_targetFunction->hasInstance(globalObject, value);
	}

	JSBoundFunction::JSBoundFunction(VM& vm, NativeExecutable* executable, JSGlobalObject* globalObject, Structure* structure, JSObject* targetFunction, JSValue boundThis, JSImmutableButterfly* boundArgs, JSString* nameMayBeNull, int length)
	: Base(vm, executable, globalObject, structure)
	, m_targetFunction(vm, this, targetFunction)
	, m_boundThis(vm, this, boundThis)
	, m_boundArgs(vm, this, boundArgs, WriteBarrier<JSImmutableButterfly>::MayBeNull)
	, m_nameMayBeNull(vm, this, nameMayBeNull, WriteBarrier<JSString>::MayBeNull)
	, m_length(length)
	{
	ASSERT(!m_nameMayBeNull \|\| !m_nameMayBeNull->isRope());
	}

	JSArray* JSBoundFunction::boundArgsCopy(JSGlobalObject* globalObject)
	{
	VM& vm = globalObject->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);
	JSArray* result = constructEmptyArray(this->globalObject(), nullptr);
	RETURN_IF_EXCEPTION(scope, nullptr);
	if (m_boundArgs) {
	// Starts with 1 since the first one is bound \|this\|.
	for (unsigned i = 1; i < m_boundArgs->length(); ++i) {
	result->push(globalObject, m_boundArgs->get(i));
	RETURN_IF_EXCEPTION(scope, nullptr);
	}
	}
	return result;
	}

	void JSBoundFunction::finishCreation(VM& vm, NativeExecutable* executable, int length)
	{
	String name; // We lazily create our 'name' string property.
	Base::finishCreation(vm, executable, length, name);
	ASSERT(inherits(vm, info()));
	}

	void JSBoundFunction::visitChildren(JSCell* cell, SlotVisitor& visitor)
	{
	JSBoundFunction* thisObject = jsCast<JSBoundFunction*>(cell);
	ASSERT_GC_OBJECT_INHERITS(thisObject, info());
	Base::visitChildren(thisObject, visitor);

	visitor.append(thisObject->m_targetFunction);
	visitor.append(thisObject->m_boundThis);
	visitor.append(thisObject->m_boundArgs);
	visitor.append(thisObject->m_nameMayBeNull);
	}

	} // namespace JSC